How is the product marketed?  If the product is marketed as daylight, full-spectrum, mimicking the sun or sunshine, or a mention of better color rendering, then you’re on the right track.  The words “white” or “soft white” will not be enough, though daylight-type lighting does have a white color versus the yellow color of traditional lighting.
 

Does the packaging or online information list the color temperature (K) and CRI?  To compare, the highest CRI is 100, which is the CRI of sunlight.  For high-quality daylight lighting, it’s likely the CRI will be above 80 and the Kelvin listing will be above 5000K.  Interestingly, just having a high CRI of 80 and above (without a high Kelvin) will not improve the color rendering capabilities of the lamp.  These two pieces of information are critical to knowing the quality of lamp you are purchasing and help you compare between competing products.  Unfortunately, CRI and the Kelvin temperature are usually not listed on the packaging or website and is something you have to ask the company about -- write or call your favorite lighting manufacturer and ask that this information be included on the packaging or at least available on a website. 

Currently, lighting manufacturers are hoping you will choose their brand instead of disclosing exactly what you are buying.  This will hopefully change as consumers demand to know more about new-technology lighting and how it is affecting them.  There might also be an opportunity for manufacturers to develop a new standard indexing or scoring system that would make it easier for consumers to understand, compare, and use lighting products.
 

Does the product produce UV?  Just about all fluorescent lighting will have some UV rays.  Daylight lighting in incandescent and halogen forms may also have some UV but likely less than fluorescent.  Nicholas Harmon, president of the daylight bulb manufacturer Verilux, notes that most sunlight-simulating lighting products with a high Kelvin and high CRI (above 90) will have some UV.  However, if the light is UL approved (look for the “UL” logo on the packaging), then the UV is not strong enough to cause a sunburn or suntan and is often considered insignificant in the lighting industry.  If you are worried about UV, compare answers from different product manufacturers as to how much, if any, UV comes from the light.  In the future, hopefully LEDs (light emitting diodes) will replace much of our current lighting choices; LEDs do not emit UV rays and use very little energy.
 

If you are looking at fluorescent bulbs, are they electric or magnetic?  The new electric fluorescents might be more healthy due to no emission of electromagnetic radiation or a low-level hum.
 

Do lumens matter?  “Wattage is used among consumers to tell how bright a light is.  But lighting people use lumens and don’t look at wattage for accuracy in brightness,” says Mark Rea of the Lighting Research Center at Polytechnic Institute in Troy, New York.  Lumens, a measurement of brightness, is almost always listed on bulb packaging but does not indicate you are purchasing daylight lighting or indicate anything else about the lamp's quality.   
 

Does the product mention any other details? Look for information on wavelength and spectral power distribution (SPD).  This may tell you how closely the product matches actual sunlight through a graphical representation.  For example, for Sylvania’s Daylight product line, you can phone the company to request CRI, Kelvin (Color Temperature), and SPD information.  Hopefully, in the future all these important  specifications will be listed on the packaging for easy consumer decision making; write to or call your favorite bulb manufacturer to ask them to make these critical packaging changes; at the very lease, this information should be available on the company's website.
 

Is the bulb dimmable?  Most fluorescent and compact fluorescent lights are either not dimmable or dim poorly.  Incandescent or halogen provide excellent dimming.  Feng Shui Expert Jayme Barrett says “As night draws near, avoid blasting light for at least an hour before bed.  Just like a sunset, allow your body’s natural cycle to slowly move toward night.”  And, New York City Lighting Consultant Steve Rubin, president of Light Designs and Electric, offers this advice “If you want the bright daytime lights with dimability, go to halogen.  You can dim down halogen to a warm color at night.”  Sun-simulating alarm clocks are also a good way to manage your dimmable light as bedtime draws near; Bio-Brite and Soleil both sell dawn/dusk simulators, which are also used as natural-waking alarm clocks (see more about these types of light-based gadgets at this Wellness Wise™ Tip Sheet).
 

What about the bulb life and energy used? The packaging should list the number of hours the bulb will last, usually something like 1000-5000 hours.  Look for the most amount of hours for the cost and energy used as another production comparison tool.  For example, Verilux sells bulbs that last a long time (5000 hours per bulb) which would mean less environmental waste per bulb, but the price also reflects this amenity.